tch: Do not log every single RTP packet and air frame
tch: Do not log every single RTP packet and air frame

The sysmoBTS takes quite a bit of CPU time for the vfprintf that
is used by osmo_hexdump. Do not dump every single frame to improve
the performance a bit.

osmocom/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts,geosphere/osmo-bts,osmocom/osmo-bts,osmocom/osmo-bts,geosphere/osmo-bts,geosphere/osmo-bts,geosphere/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts